Once chastised for not being tough enough, President Barack Obama has lately been getting personal with his political adversaries — singling them out for scorn in speeches, interviews, asides and even in his weekly radio address.

Rather than just going after big groups of bad guys — insurance companies, lobbyists, the media — Obama has adopted a strategy that gives a face to the enemy.

By setting himself up against specific opponents, he provides a point of contrast that’s useful in invigorating a base hungry for bare knuckles and bravado — and forces those in the middle to choose between him and his villain du jour.

“He lost some of his spunk and fight. He lost what he had in the campaign. When you campaign, you campaign against people,” said Paul Stob, a Vanderbilt professor who co-operates the website www.presidentialrhetoric.com. “I think there have been very conscious decisions to get back to that.” With his approval numbers flat-lining near the 50 percent mark in recent months — and Democrats trailing Republicans by double digits among independents in recent surveys — the president and his congressional allies could use a boost among both core Democratic constituencies and folks who feel no particular allegiance to either party.

Republicans say the president’s return to confrontational, campaign-style politics is beneath his office. “The presidency is the highest office of the land, and when he differs, he should differ on policy [and] on principle,” said Ari Fleischer, who was the White House press secretary under President George W. Bush. “He’s entitled to fight and defend himself, but not in ad hominem personal style. It’s unseemly for a president to do that.”

Republicans also depict Obama’s approach as a sign of weakness born of a loss of traction on the issues.

Deputy White House press secretary Bill Burton describes a West Wing that gets personal when Obama’s aides believe the other side is distorting the truth — and the media are playing along. “When he was a candidate, President Obama said as president he would tell people what they needed to hear not just what they wanted to hear. And that includes telling hard truths to folks who are his friends and who are his political opponents,” Burton said.